Optical differential reflectance spectroscopy of ultrathin epitaxial organic films

Abstract

This Perspective does not have the ambition to entirely review the subject of optical spectroscopy on thin organic films. What we will try to achieve instead is to give an overview on optical reflectance spectroscopy of highly ordered organic thin films in the thickness range from submonolayers to several monolayers, as a tool to study the absorption behavior of such films. By doing so, we will emphasize the relations between the physical layer structure and the resulting optical properties. More specifically, we intend to show on the basis of particular examples what physical effects can be favorably examined by means of real-time optical spectroscopy, i.e., applied during the actual film growth, especially differential reflectance spectroscopy (DRS). Epitaxial organic films on inorganic substrates (insulators and conductors) will be in focus, and also the perspectives of investigating organic-organic heteroepitaxial layers will be addressed.

Integer Charge Transfer and Hybridization at an Organic Semiconductor/Conductive Oxide Interface

“…[25][26][27] Briefly, the photon energy-and film thickness-dependent reflectance was measured in situ in ultrahigh vacuum. The optical functions of the glass substrate and the bare ZnO film were determined separately by transmission and reflectance measurements in an ex situ Varian Cary 5000…”

Real-time monitoring of 2D semiconductor film growth with optical spectroscopy

“…The DR signal R R D thus reveals the change of the optical reflectivity with respect to the clean α-Al 2 O 3 (0001) surface as a function of the deposition time t [27].…”

“…An acquisition time of 2 s per spectrum was used to collect all the spectra used in this paper. The DR spectra are then obtained from [27]:…”

Optical Constants of α‐ and β‐Zinc(II)‐Phthalocyanine Films

“…The determination of the optical constants is possible by means of a simultaneous analysis of transmission (T) and reflectance (R) spectra. However, here the reflectance data were replaced by differential reflectance spectra (DRS) [11][12][13]. Thereby, the need for a calibrated mirror can be avoided.…”